|
(11) | EP 2 712 025 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
|
|
| (54) |
Communication device and antennas with high isolation characteristics Kommunikationsvorrichtung und Antennen mit Hochisolationsmerkmalen Dispositif de communication et antennes ayant des caractéristiques d'isolation élevées |
|
|
|||||||||||||||||||||||||||||||
| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This Application claims priority of Taiwan Patent Application No. 101134407 filed on September 20, 2012, the entirety of which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The disclosure generally relates to a communication device, and more particularly, relates to a communication device comprising a dual-antenna system with high isolation characteristics.
Description of the Related Art
[0003] When mobile technology transmission rates increase, more and more antennas are required to be designed into mobile devices in order to increase data transmission amounts. Accordingly, a general antenna system (e.g., a dual-antenna WWAN (Wireless Wide Area Network) system which has functions of dual-SIM (Subscriber Identity Module), dual-standby, and dual-talk) is preferably disposed at one end of a handheld device (e.g., the bottom of a mobile phone) so that the bandwidth and the SAR (Specific Absorption Rate) of the antenna system can easily meet requirements. However, it is difficult to improve the isolation of the antenna system for WWAN high bands (e.g., a GSM1800/1900 band). The main reason is for this, is that mutual coupling between antennas increases since surface currents on a ground plane of a mobile device are easily excited along an antenna system operating at high bands. Thus, maintaining a high amount of isolation and reducing mutual coupling and interference between antennas in a limited space of a mobile device are critical challenges for antenna designers. In the prior art documents JP 2006 11 5182 A1, WO 02/05382 A1, and EP 2 230 717 A1, antenna systems with multiple antennas are disclosed.
BRIEF SUMMARY OF THE INVENTION
[0004] To solve the problems in the prior art, the invention provides a communication device comprising a first antenna and a second antenna that are both disposed at one end of the communication device. The two antennas have good isolation therebetween when operating in the WWAN high bands (e.g., a GSM1800/1900 band).
[0005] The invention is defined by the independent claim, optional features are set out in the dependent claims.
BRIEF DESCRIPTION OF DRAWINGS
[0006] The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
FIG. 1A is a diagram for illustrating a communication device according to a first embodiment of the invention;
FIG. 1B is a diagram for illustrating a communication device according to a second embodiment of the invention;
FIG. 2 is a diagram for illustrating S parameters of an antenna system of a communication device according to the first embodiment of the invention;
FIG. 3 is a diagram for illustrating a communication device according to a first example.
FIG. 4 is a diagram for illustrating a communication device according to a second example; and
FIG. 5 is a diagram for illustrating a communication device according to a third embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0007] In order to illustrate the foregoing and other purposes, features and advantages of the invention, the embodiments and figures thereof in the invention are shown in detail as follows.
[0008] FIG. 1A is a diagram for illustrating a communication device 100 according to a first embodiment of the invention. As shown in FIG. 1A, the communication device 100 comprises a ground element 10 and an antenna system. The ground element 10 comprises a protruded ground plane 101 and a main ground plane 104. The main ground plane 104 and the protruded ground plane 101 of the ground element 10 substantially form an L-shape. The antenna system comprises a first antenna 11 and a second antenna 12. In some embodiments, the first antenna 11 comprises a metal radiation element (not shown). The first antenna 11 is adjacent to the main ground plane 104 of the ground element 10. More particularly, at least two sides of the first antenna 11 are adjacent to the main ground plane 104 and the protruded ground plane 101 of the ground element 10, respectively. In some embodiments, the second antenna 12 is a slot antenna. The second antenna 12 is formed in the protruded ground plane 101 of the ground element 10, and the protruded ground plane 101 is adjacent to the first antenna 11. The first antenna 11 is excited by a first signal source 14, and the second antenna 12 is excited by a second signal source 15 through a feeding microstrip line 13. In some embodiments, the second antenna 12 is an open slot antenna and has an open end 121. The open end 121 of the second antenna 12 is disposed at a specific edge of the protruded ground plane 101, e.g., the edge 102, and the edge 102 is not adjacent to the first antenna 11. In this embodiment, the second antenna 12 further comprises a closed end 122, and the closed end 122 of the second antenna 12 is closer to the first antenna 11 than the open end 121 of the second antenna 12.
[0009] FIG. 1B is a diagram for illustrating a communication device 150 according to a second embodiment of the invention. The second embodiment is similar to the first embodiment. As shown in FIG. 1B, the communication device 150 further comprises a circuit board 19 (or a dielectric substrate 19) which is disposed inside of the communication device 150. The ground element 10 is formed on the circuit board 19. More particularly, the circuit board 19 has two opposite surfaces E1 and E2. The ground element 10 is disposed on the surface E1 of the circuit board 19, and the feeding microstrip line 13 is disposed on the surface E2 of the circuit board 19. In the embodiment, the first antenna 11 comprises a metal radiation element 112 which substantially has an inverted J-shape. Note that the invention is not limited to the above. In other embodiments, the metal radiation element 112 may have other shapes, for example, a U-shape, an L-shape, a spiral shape, or an irregular shape. Other features of the communication device 150 in the second embodiment are similar to those in the first embodiment. Accordingly, the performance of the communication device 150 in the second embodiment is almost the same as that of the first embodiment.
[0010] FIG. 2 is a diagram for illustrating S parameters of the antenna system of the communication device 100 according to the first embodiment of the invention. The horizontal axis represents operation frequency (MHz), and the vertical axis represents S parameters (dB). As shown in FIG. 2, the reflection coefficient (S11) curve 22 represents the reflection coefficient (S11) of the first antenna 11, and the reflection coefficient (S22) curve 23 represents the reflection coefficient (S22) of the second antenna 12, and the isolation (S21) curve 24 represents the isolation (S21) between the first antenna 11 and the second antenna 12. The first antenna 11 generates a resonant mode in at least one mobile communication band 21 (e.g., a GSM1800/1900 band). The second antenna 12 also generates a resonant mode in at least the mobile communication band 21. In a preferred embodiment, the isolation (S21) between the first antenna 11 and the second antenna 12 is lower than about -16dB, and lower than about -20dB, in the mobile communication band 21.
[0011] In some embodiments, the element sizes are as follows. The circuit board 19 has a length of about 110mm, a width of about 60mm, and a thickness of about 0.8mm. The first antenna 11 has a length of about 25mm, a width of about 10mm, and a height of about 3mm. A slot of the second antenna 12 has a length of about 23mm. In some embodiments, the area occupied by the antenna system is merely about 600mm2 (60mm by 10mm). The antenna system of the invention is preferably disposed at a same edge of a smart phone, and furthermore, the antenna system is very thin and can be manufactured easily. Accordingly, the invention can be applied to a variety of slim mobile communication devices, for example, a mobile phone, a tablet computer, or a notebook computer. Note that the above element sizes, element parameters and frequency ranges are not limitations of the invention, and they may be adjusted by a designer according to different requirements.
[0012] FIG. 3 is a diagram for illustrating a communication device 300 according to a first example. The first example is similar to the first embodiment. The difference from the first embodiment is that an open end 321 of a second antenna 32 of the communication device 300 is disposed at another specific edge of the protruded ground plane 101, e.g., an edge 103. Similarly, the open end 321 of the second antenna 32 is not adjacent to the first antenna 11. In this example the second antenna 32 further comprises a closed end 322, and the closed end 322 of the second antenna 32 is closer to the first antenna 11 than the open end 321 of the second antenna 32. Other features of the communication device 300 in the first example are similar to those in the first embodiment. Accordingly, the performance of the communication device 300 in the first example is almost the same as that of the first embodiment.
[0013] FIG. 4 is a diagram for illustrating a communication device 400 according to a second example. The second example is similar to the first embodiment. The difference from the first embodiment is that an open end 421 of a second antenna 42 of the communication device 400 is disposed at another specific edge of the protruded ground plane 101, e.g., an edge 103. Similarly, the open end 421 of the second antenna 42 is not adjacent to the first antenna 11. In the second example, the open end 421 of the second antenna 42 is closer to the first antenna 11 than a closed end 422 of the second antenna 42. Other features of the communication device 400 in the second example are similar to those in the first embodiment. Accordingly, the performance of the communication device 400 in the second example is almost the same as that of the first embodiment.
[0014] FIG. 5 is a diagram for illustrating a communication device 500 according to a third embodiment of the invention. The third embodiment is similar to the first embodiment. The difference from the first embodiment is that the communication device 500 further comprises an electronic component 56. As shown in FIG. 5, the electronic component 56 is disposed on the protruded ground plane 101 of the ground element 10, and the electronic component 56 is substantially disposed between the first antenna 11 and the second antenna 12. In some embodiments, the electronic component 56 is a data transmission component or a microphone, and the electronic component 56 is disposed in such a manner that the design space of the ground element 10 is used effectively and the antenna system is integrated with relative electronic components. Other features of the communication device 500 in the third embodiment are similar to those in the first embodiment. Accordingly, the performance of the communication device 500 in the third embodiment is almost the same as that of the first embodiment.
[0015] Use of ordinal terms such as "first", "second", "third", etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.
[0016] It will be apparent to those skilled in the art that various modifications and variations can be made in the invention. It is intended that the standard and examples be considered as exemplary only, with a true scope of the disclosed embodiments being indicated by the following claims and their equivalents.
a ground element (10), comprising a main ground plane (104) and a protruded ground plane (101), the main ground plane (104) and the protruded ground plane (101) substantially form an L-shape and the protruded ground plane (101) has a specific edge (102); and
an antenna system, comprising:
a first antenna (11), comprising a metal radiation element, and being adjacent the main ground plane (104) and the protruded ground plane (101); and
a second antenna (12), being an open slot antenna, that is formed in the protruded ground plane (101), the second antenna (12) has an open end (321) and a closed end, the open end (321) being disposed at the specific edge (102) of the protruded ground plane (101), and the specific edge (102) is arranged opposite to the edge of the protruded ground plane (101) adjacent the first antenna (11),
characterized in that
the open slot antenna substantially has a U-shape.
einem Masseelement (10), das eine Hauptmasseebene (104) und eine hervorstehende Masseebene (101) aufweist, wobei die Hauptmasseebene (104) und die hervorstehende Masseebene (101) im Wesentlichen eine L-Form bilden und die hervorstehende Masseebene (101) einen spezifischen Rand (102) aufweist; und
einem Antennensystem, mit:
einer ersten Antenne (11), die ein metallisches Strahlungselement aufweist und benachbart zur Hauptmasseebene (104) und zur hervorstehenden Masseebene (101) angeordnet ist; und
einer zweiten Antenne (12), die eine in der hervorstehenden Masseebene (101) ausgebildete offene Schlitzantenne ist, wobei die zweite Antenne (12) ein offenes Ende (321) und ein geschlossenes Ende aufweist, wobei das offene Ende (321) an dem spezifischen Rand (102) der hervorstehenden Masseebene (101) angeordnet ist und der spezifische Rand (102) gegenüberliegend dem Rand der hervorstehenden Masseebene (101) angeordnet ist, der der ersten Antenne (11) benachbart ist;
dadurch gekennzeichnet, dass
die offene Schlitzantenne im Wesentlichen eine U-Form hat.
un élément de terre (10), comprenant un plan de sol principal (104) et un plan de sol en saillie (101), le plan de sol principal (104) et le plan de sol en saillie (101) constituent essentiellement une forme en L et le plan de sol en saillie (101) a un bord spécifique (102) ; et
un système d'antenne, comprenant :
une première antenne (11) comprenant un élément de rayonnement métallique et étant adjacente au plan de sol principal (104) et au plan de sol en saillie (101) ; et
une seconde antenne (12) étant une antenne à fente ouverte qui est formée dans le plan de sol en saillie (101), la seconde antenne (12) a une extrémité ouverte (321) et une extrémité fermée, l'extrémité ouverte (321) étant disposée au niveau du bord spécifique (102) du plan de sol en saillie (101) et le bord spécifique (102) étant agencé à l'opposé du bord du plan de sol en saillie (101) adjacent à la première antenne (11),
caractérisé en ce quel'antenne à fente ouverte a une forme essentiellement en U.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description